Two prominent GOP lawmakers are pressing Secretary of State Rex Tillerson for an explicit timeline detailing when senior State Department officials first received evidence that sonic attacks in Cuba had occurred.

All five Cuban-American House members have asked the Government Accountability Office, Congress’s nonpartisan auditing and investigative arm, to determine whether the State Department mishandled its response to a series of mysterious sonic attacks on at least 24 U.S. diplomats in Cuba.

The State Department has repeatedly declined to provide a specific timeline of when officials first became aware of mysterious attacks on U.S. diplomats in Cuba—even after a new accusation from a victim that U.S. officials ignored his complaints.